خيارات البحث
النتائج 251 - 260 من 546
Plasmodium berghei-induced malaria decreases pain sensitivity in mice
2021
Aboyeji L. Oyewole | Oluwole Akinola | Bamidele V. Owoyele
Various types of pain were reported by people with Plasmodium falciparum and were mostly attributed to a symptom of malarial infection. Neural processes of pain sensation during malarial infection and their contributions to malaria-related death are poorly understood. Thus, these form the focus of this study. Swiss mice used for this study were randomly divided into two groups. Animals in the first group (Pb-infected group) were inoculated with Plasmodium berghei to induce malaria whilst the other group (intact group) was not infected. Formalin test was used to assess pain sensitivity in both groups and using various antagonists, the possible mechanism for deviation in pain sensitivity was probed. Also, plasma and brain samples collected from animals in both groups were subjected to biochemical and/or histological studies. The results showed that Pb-infected mice exhibited diminished pain-related behaviours to noxious chemical. The observed parasite-induced analgesia appeared to be synergistically mediated via µ-opioid, α2 and 5HT2A receptors. When varied drugs capable of decreasing pain threshold (pro-nociceptive drugs) were used, the survival rate was not significantly different in the Pb-infected mice. This showed little or no contribution of the pain processing system to malaria-related death. Also, using an anti-CD68 antibody, there was no immunopositive cell in the brain to attribute the observed effects to cerebral malaria. Although in the haematoxylin and eosin-stained tissues, there were mild morphological changes in the motor and anterior cingulate cortices. In conclusion, the pain symptom was remarkably decreased in the animal model for malaria, and thus, the model may not be appropriate for investigating malaria-linked pain as reported in humans. This is the first report showing that at a critical point, the malaria parasite caused pain-relieving effects in Swiss mice.
اظهر المزيد [+] اقل [-]Review of African swine fever outbreaks history in South Africa: From 1926 to 2018
2021
Ciza A. Mushagalusa | Eric Etter | Mary-Louise Penrith
The article reviews the outbreaks and distribution of African swine fever (ASF) in South Africa since the first probable outbreak that occurred in the Koedoesrand Ward in 1926. Retrospective data on the ASF outbreaks in South Africa were obtained from the World Organisation for Animal Health (OIE) disease database and the South African veterinary services annual reports in addition to published articles and online sources. South Africa has experienced many outbreaks that can be divided into 2 time periods: the period before the development of the OIE diseases database (1993) and the period after. More than 141 outbreaks of ASF were reported during the first period. Since the development of OIE disease database, 72 outbreaks directly involving 2968 cases, 2187 dead and 2358 killed pigs mainly in smallholder pig farms were reported. The median number of cases for a given ASF outbreak is 17, but in 50% of outbreaks no pigs were killed for prevention. The most important ASF outbreak was reported in April 2014 in the Greater Zeerust district (North West province) involving 326 cases and 1462 killed pigs. However, the outbreak with highest mortality involving 250 pigs was reported in 2016 (Free State province). According to phylogenetic analysis, nine p72 genotypes (I, III, IV, VII, VIII, XIX, XX, XXI and XXII) have been identified in South Africa. Season-wise, more outbreaks were recorded during summer. It was also observed that the OIE disease database could contain errors that would have been introduced through compiled forms at country level. Spatiotemporal studies on ASF outbreaks in South Africa are therefore required in order to assess statistically and quantitatively the clustering of outbreaks over space and time.
اظهر المزيد [+] اقل [-]Acknowledgement to reviewers
2021
Editorial Office
No abstract available.
اظهر المزيد [+] اقل [-]Wide circulation of peste des petits ruminants virus in sheep and goats across Nigeria
2021
Samuel E. Mantip | Anthony Sigismeau | Maurice Nanven | Atuman Joel | Abayomi M. Qasim | Sada Aliyu | Ibrahim Musa | Ogechukwu Ezeanyika | Ibikunle Faramade | Garba Ahmed | Timothy Y. Woma | David Shamaki | Genevieve Libeau | Souaibou Farougou | Arnaud Bataille
Peste des petits ruminants (PPR) is a highly contagious viral disease that mainly affects goats and sheep in Asia, Africa and the Middle East, and threatens Europe [R.E.1]. The disease is endemic on the African continent, particularly in West Africa, and is a major factor driving food insecurity in low-income populations. The aim of this research study was to carry out surveillance, genetic characterisation and isolation of recently circulating PPR viruses (PPRV) in sheep and goats from the six agro-ecological zones of Nigeria. A total of 268 post-mortem tissue samples of lung and mesenteric ganglia were collected from clinically suspected sheep and goats in 18 different states, of which five never previously sampled. The presence of PPRV was confirmed using a reverse-transcription coupled with a polymerase chain reaction (RT-PCR) assay. A total of 72 samples, 17 sheep (6%) and 55 goats (21%), were found to be PPR positive. Positive samples were distributed in almost all states, except Kano, where PPR was detected in previous studies. The PPRV-positive samples were further confirmed by sequencing or virus isolation in areas where the infection had never previously been detected. These results confirm the active circulation of PPRV across all six agro-ecological zones of Nigeria, and consequently, the need for introducing strict measures for the control and prevention of the disease in the country.
اظهر المزيد [+] اقل [-]Association between extract from fruit of Opuntia ficus-indica and streptozotocin-induced diabetic rats
2021
Jo, H.M. | Kim, H.S. | Kim, D.J. | Sim, S.B.
Opuntia ficus-indica has traditionally been used in prevention and treatment of various diseases such as diabetes mellitus. The current study was performed to determine whether Opuntia ficus-indica is associated with diabetes. Diabetic rat models were induced with streptozotocin (STZ). This study divided rats into 1 day (short-term) and 4 consecutive weeks (long-terms) of daily administration. These groups were subdivided into four groups each other for assessment of blood glucose level as follows: Group 1, untreated rats given distilled water; Group 2, untreated rats given Opuntia ficus-indica; Group 3, STZ-induced diabetic rats given distilled water; Group 4, STZ-induced diabetic rats given Opuntia ficus-indica. Blood glucose level was measured for one day and four weeks. In addition, serum markers of alanine aminotransferase (ALT), aspartate transaminase (AST), cholesterol, and creatinine were determined, and total protein triglycerides were measured at four weeks. Blood glucose level was highest in both groups (Group 3 and Group 4) at 30 minutes and two weeks and gradually decreased in a time-dependent manner. The difference in blood glucose among the four groups was significant (p < 0.05). Additionally, the levels of ALT, AST and triglycerides were significantly decreased by Opuntia ficus-indica.
اظهر المزيد [+] اقل [-]A retrospective study of 16 cats with intermediate- to high-grade alimentary lymphoma
2021
Kwak, D.H. | Cho, M.J. | Park, H.J. | Song, K.H. | Seo, K.W.
The purpose of this retrospective study was to describe cases of feline intermediate- to high-grade alimentary lymphoma regarding signalment, clinical presentation, laboratory findings, response to therapy (modified 25-week University of Wisconsin-Madison [UW-25] vs. COP [cyclophosphamide, vincristine, prednisone]), toxicosis, and outcomes and to identify prognostic factors. Sixteen cats were treated with chemotherapy protocols. Response rates and survival did not differ statistically between the two protocols. The progression-free interval (PFI) and median survival time (MST) in cats achieving a response to therapy were longer than in those with no response [NR] (complete remission [CR] vs. partial remission [PR] vs. NR; PFI, 124 vs. 49 vs. 12 days, p < 0.001; MST, 361 vs. 118 vs. 16 days, p < 0.001). Clinical stage was another prognostic factor for PFI and MST. The PFI and MST in cats in stage I were longer than in those in other stages (PFI, 107 days vs. 30 days; MST, 193 days vs. 54 days). Hematologic and gastrointestinal toxicosis was mostly low grade. In comparing the modified UW-25 protocol with the COP protocol, there was not much difference in the number of neutropenic episodes and grade levels.
اظهر المزيد [+] اقل [-]Clinical profile of Asian and African strains of Zika virus in immunocompetent mice
2021
Shin, M.N. | Kim, J.I. | Park, J.H. | Hahn, T.W.
The mosquito-borne pathogen Zika virus may result in neurological disorders such as Guillain-Barré syndrome and microcephaly. The virus is classified as a member of the Flaviviridae family and its wide spread in multiple continents is a significant threat to public health. So, there is a need to develop animal models to examine the pathogenesis of the disease and develop vaccines. To examine the clinical profile during Zika virus infection, we infected neonatal and adult wild-type mice (C57BL/6 and Balb/c) and compared the clinical signs of African-lineage strain (MR766) and Asian-lineage strain (PRVABC59, MEX2-81) of Zika virus. Consistent with previous reports, eight-week-old female Balb/c mice infected with these viral strains showed changes in body weight, survival rate, and no neurologic signs, but demonstrated increases in the weights of spleens and hearts. However, one-day-old neonates showed significantly lower survival rate and body weight with the African-lineage strain than the Asian-lineage strain. These results confirmed the pathogenic differences between Zika virus strains. We also evaluated the clinical responses in neonatal and adult mice of different strains. Our findings suggest that these are useful mouse models for characterization of Zika virus for vaccine development.
اظهر المزيد [+] اقل [-]Construction of an avian hepatitis E virus replicon expressing heterologous genes and evaluation of its potential as an RNA vaccine platform
2021
Moon, H.W. | Sung, H.W. | Park, J.H. | Kwon, H.M.
To evaluate avian hepatitis E virus (aHEV) as an RNA vaccine platform, ORF2 of aHEV was replaced by heterologous genes, such as eGFP and HA-tag, in aHEV infectious cDNA clones. eGFP and HA-tag replicons were expressed in LMH cells. To confirm expression of the heterologous protein, ORF2 was replaced with the antigenic S1 gene of IBV. The IBVS1 replicon was expressed in LMH cells. To our knowledge, this is the first investigation the showing potential as a RNA vaccine platform using an aHEV. In the future, it may be used in the development of RNA vaccines against various pathogens.
اظهر المزيد [+] اقل [-]A study on the improvement of the score system in the hazard analysis and critical control points prerequisite program for meat shops in Korea
2021
Baek, S.H. | Nam, I.S.
This study is to develop a new scoring system for rating Hazard analysis and critical control points prerequisite evaluation items for meat shops to provide a more objective and accurate evaluation of food safety compliance. The importance of each item was measured by looking at the hazard severity level and the rate of non-compliance associated with it. It was found that the new scoring system is more stringent and gives a clearer picture of compliance with the most critical safety standards, and therefore is expected to have a positive effect on the hygiene and safety of livestock products.
اظهر المزيد [+] اقل [-]Inhibitory effects of fenbendazole, an anthelmintics, on lipopolysaccharide-activated mouse bone marrow cells
2021
Park, S.R. | Joo, H.G.
Fenbendazole (FBZ) is a commonly used anthelmintic in veterinary medicine that has recently been found to have anticancer effects in humans. On the other hand, few studies have examined the anti-inflammatory effects of FBZ, and its mechanism is unknown. In this study, mouse bone marrow cells (BMs) were treated with lipopolysaccharide (LPS), a representative inflammation-inducing substance, to generate a situation similar to osteomyelitis in vitro. The effect of FBZ on inflammatory BMs was examined by measuring the metabolic activity, surface marker expression, cell nuclear morphology, and mitochondrial membrane potential (MMP) of BMs. FBZ decreased the metabolic activity and MMP of LPS-treated BMs. Annexin Ⅴ-fluorescein isothiocyanate/propidium iodide staining and Hoechst 33342 staining showed that FBZ reduced the number of viable cells and induced the cell death of inflammatory BMs. In addition, FBZ reduced the proportion of granulocytes more than B lymphocytes in LPS-treated BMs. Overall, FBZ induces cell death by destabilizing the MMP of LPS-induced inflammatory BMs. FBZ can play a role as an anthelmintic and anticancer agent and an anti-inflammatory agent.
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